Boiler



Aug. 21, 1962 W. A. HALE BOILER 4 Sheets-Sheet l Filed Feb. 19. 1960 fiala i fnl/s172271" k/la'am A. Hale Aug. 21, 1962 w. AgHALE BOILER Filed Feb. 19. 1960 4 Sheets-Sheet 2 fnl/527.7271" W Za'am A. Haie W. A. HALE Aug. 21, 1962 BOILER 4 Sheets-Shea?l 3 Filed Feb. 19, 1960 vL /f -34 fnl/E' 27.70F Wh'am A. Haie WM Aug- 21, 1962 w. A. HALE 3,050,041

BOILER.

Filed Feb. 19, 1960 4 Sheets-Sheet 4 fnI/Enfar' Wz'llnm Ah'ale.

United States Patent @ffice Patented Aug. 2l, 1962 3,050,041 BOILER William A. Hale, 4503 N. Knoxville Ave., Peoria, Ill. Filed Feb. 19, 1960, Ser. No. 9,988 4 Claims. (Cl. 122-367) The present invention relates to hot water yor steam boilers and is, more particularly, concerned with the construction of an extremely comp-act `and ultra eicient boiler particularly `adapted to residential use.

As those familiar with the building trades and home heating are aware, the construction of residential homes of varying sizes in lany given location requires a corresponding variation in the heating plant designed for the residence. Further, of course, construction of the same type of residence in various geographical locations may likewise call for a variation in capacity of the heating unit designed for the residence. Accordingly, it is desirable in the construction of residential, or for that matter commercial, boiler apparatus, that the apparatus be modied easily to accommodate various capacities. While such modication is extremely desirable, it is important that heating efficiency be retained at a high level throughout the range of intended modiiication so that the boiler unit will provide economical operation in its various installations.

In addition to the problems -mentioned above, those familiar with the construction of single story buildings are aware that the relatively short chimney ordinarily associated with such construction provides only a limited natural draft. It is extremely important in boiler construction that a negative `draft be provided in the boiler firebox at all times to promote clean combustion of the fuel. In many prior art boiler structures with which I am familiar, bafes and similar air flow obstructions employed for purposes of absorbing heat from the -boiler iire have suciently damped 4the flow of air to practically eliminate the draft in the iirebox or create a positive pressure over the lire resulting in incomplete combustion. In such prior art structures employing baiiles, it has been found that even where the bales are initially acceptable, the accumulation of soot `during normal tiring of the boiler eventually decreases the bailie passages to a point where the draft is insutiicient for satisfactory operation. On the other hand, it has been found with prior art boiler constructions, that elimination of the baffles has rendered the boiler apparatus insufliciently efficient to utilize the heat of the fire with a resultant unsatisfactorily high stack temperature.

The boiler apparatus of the present invention has provided a novel and substantially improved boiler construction which is readily modified for various vboiler capacities. Further, the boiler employs no bafes in the usual sense, thereby utilizing substantially the entire natural draft provided by even the short chimneys of one story buildings. These important advantages are achieved, however, without in any way rendering the boiler ineicient or in any way raising the stack temperature above a desired value. Additionally, the construction of the boiler in accordance with the present invention permits extremely lightweight materials to be employed since the boiler may be constructed within the provisions of the miniature boiler code. This construction is accomplished even though the boiler `output compares with that of much larger prior art boiler units.

More particularly, the improved boiler of the present invention comprises a generally cylindrical main boiler shell containing liquid to be heated. The shell is less than 16 in diameter placing the shell Within the miniature boiler provisions of the Steel Boiler Institute Code. A burner chamber is positioned immediately below the horizontally disposed boiler shell and the surface of the shell immediately labove the rebox or fire chamber is provided with generally longitudinally extending tins. Heat from the iirebox irnpinges directly upon the lfinned lower portion of the shell thereby transferring a substantial amount of the heat generated in the fire. The air ilow from the rebox is split by the main shell `and passes upwardly around both sides ott the shell tot a generally centrally located flue outlet to the stack. Peripheral metal channels are provided for directing the hot air ow upwardly around the main shell t0 the centrally located outlet. These channels provide a scrubbing heat Contact and heat transfer action between the llowing gases and the shell in a manner removing a substantial portion of the heat remaining in the upwardly moving air following absorption of heat by the finned portion of the main shell. It has been found that as a result of the operation of the device described, stack temperatures in the desired temperature range are readily achieved without baied boiler passaegs or other of the prior art devices that have impaired the eciency of the boiler operation.

Additionally, in accordance with the present invention, a boiler is provided capable of accommodating -a highly eicient hot water heater without modifying the external configuration of the boiler or in any Way impairing its efficiency.

It is, accordingly, an object of the present invention to provide a compact, highly efficient, hot Iwater boiler.

Another object of the present invention is to provide an improved small size hot water boiler having an unusually large heat transfer surface in substantially direct contact with tirebox gases.

Yet another object of the present invention is to provide an eflicient boiler construction capable of operating at a low stack temperature without employing combustion gas flow restriction bafiles.

Still a further object of the present invention is to provide a novel and substantially improved compact boiler construction employing a generally cylindrical main boiler shell having both longitudinal and peripheral heat conducting lins connected therewith.

Yet another object of the invention is to provide a simplified generally cylindrical boiler having a generally horizontally disposed main boiler shell carrying a generally horizontally disposed hot water heater.

Still a further object of the invention is to provide an inexpensive highly ellicient hot water boiler capable of simple modiication to accommodate a large number of boiler capacities.

A feature of the invention is the provision of a generally cylindrical horizontally disposed main boiler shell having a plurality of peripheral channels requiring the ow of c-ombustion gases vertically around the sides of the shell and in scrubbing contact therewith.

Another feature of the present invention is the construction of a boiler having a generally horizontally disposed main boiler shell co-operating with a substantially vertical draft and employing no xed balies for materially restricting dlow of the combustion gases through the boiler unit.

Still other and further objects and features of the present invention will become apparent to those skilled in the art from a consideration of the attached specilication and drawings wherein a preferred embodiment of the invention is shown, by way of illustration only, and wherein:

FIGURE l is an end elevational view, partially broken away, of a boiler constructed in accordance with the principles of the present invention;

FIGURE 2 is a cross-sectional view, in plan, taken along the line II-II of FIGURE l;

FIGURE 3 is a View in cross-section looking upwardly, and taken along the line III-III of FIGURE 1;

FIGURE 4 is a cross-sectional view taken through the .a main boiler shell of the boiler construction of the present invention, and taken along the line IV-IV of FIGURE 1; and

FIGURE 5 is a plan view of the blank used in constructing individual flow channels.

As shown on the drawings:

As may be seen from a consideration of FIGURE l of the drawings, the boiler of the present invention comprises, generally, a heat exchanger comprising a generally horizontally disposed cylinder supported on a vertically rising casing 11 forming a combustion chamber 12 above a direbox l9 which in turn has a generally horizontally disposed fuel inlet 13. Fuel is introduced via inlet 13 by conventional burner equipment adapted for the combustion of liquid, gaseous or solid fuel. Upon introduction into the irebox 9, the fuel is ignited, again by any conventional igniting means. The burning gases proceed vertically upwardly in the combustion chamber 12 and impinge directly on the downwardly facing portion 15 of the generally cylindrical main shell 16 of the heat eX- changer 10. This downwardly facing portion, forming the top surface of the combustion chamber, is commonly termed the crown sheet and is provided with longitudinally extending ribs 17 of heat conducting metal. The moving combustion gases are divided laterally and pass upwardly in the direction of arrows 18 between the shell 16 and casing `19 via guide channels 20 and thence vertically upwardly via outlet flue 21 to a conventional stack by which they are discharged to atmosphere. The entire boiler apparatus is conveniently enclosed in an outer shroud or housing 25.

With the above general configuration ofthe boiler components in mind, particular structural details may be observed from a consideration of the sectional views in FIG- URES 2, 3 and 4. Thus, it will be observed in FIGURE 2 that the fuel inlet 13 is provided with a flange 26 to which a conventional burner element may be secured. Fuel is introduced via the inlet 13 in the direction of arrows 27 for ignition and combustion in the rebox 9 and combustion chamber area 12. The rebox is formed by respective layers of rebrick and tire clay 28A and 29 which provide a generally upright cylindrical chamber form. The outside of the chamber is formed by a generally cylindrical sheet metal casing 30. Likewise illustrated in FIGURE 2, the combustion chamber 12 comprises a generally rectangular volume having side walls 31, 32, 313 and 34 of sheet metal backed by insulating material 35. At the junction between the top of the generally circular rebox and the combustion chamber, a rectangular block of insulating material 36 is provided. This material is provided with a circular cutfout indicated at 37 providing communication between the rebox and the combustion chamber 1,2.

As shown in the upwardly facing cross-sectional view of FIGURE 3, the crown sheet or downwardly facing surface 15 of the cylindrical main shell 16 is providedwith a plurality of longitudinally extending heat conducting tins 17. These tins are secured along their lengths to the main shell 16, preferably by a continuous weld along one edge thereof, for example, as at 17a in FGURE 1. As may be seen from a consideration of FIGURES 1 and 3', the fins 17 do not extend laterally a suiiicient distance to abut against the combustion chamber walls 31 and 33. Instead, a flo w passage is provided at 18, between the main shell V16 and the outer sheet metal casingv 19. As above noted, combustion gases leaving the combustion chamber 12 pass upwardly around' the main shell of the boiler via passageways 18, and arcuate channels 20.

Control of the flow of the combustion gases around the main shell is clearly observed in FIGURE 4. There, it will be observed that thirteen channels are provided on each side of the main shell 16. Each channel comprises an outer peripheral surface l 2da generally radially inwardly projecting sides 2Gb and 29C and longitudinally extending flange portions 20d and 29e. Each of the channels 20 may be constructed from a fiat sheet 4 of material, such as for example, aluminized steel, of a configuration generally illustrated in FIGURE 5. As may be seen, each of the strips 20 is notched as at 20f. The strip is subsequently bent along the lines 20g, 20h, Ztlz', and 20j to provide the cross-sectional configuration illustrated in FIGURE 4. The surface 20a may then be struck into an are to provide the linal form shown in FIGURE l where the notches Zlf are substantially closed and the anges 20d and 20e form generally to the main shell 16 and are welded thereto as at 20k.

Alternatively, the channels 20 may be die stamped from a plain, unnotched blank into their final shape, in which case a larger blank may be used and more than a single channel may be stamped at one time.

As a result of the arcuate configuration of the channels 26, a substantial portion of the combustion gases are forced to scrub against the peripheral surfaces 20a. This scrubbing action causes an etlicient heat transfer from the gases to the heat conducting met-al of the channels Ztl, and further, causes a deiiection of the gases against the outer shell 16 providing intimate contact of the gases with the shell within the channels 20. While the channels 20 accordingly provide extremely efiicient heat transfer action, it will be noted that they in no way provide blocking baffles or other impediments to the ow of the combustion gases around the main shell 16.

As the combustion gases leave the upper ends of the channels 20, and the area between the channels, they pass out to the stack (not shown) via ue 21. The iiue 21 is provided with a vertically sliding sleeve 21a which may be adjusted vertically and locked in adjusted position by screw 2lb. If desired, slight adjustment of the sleeve 21a may from time to time be made to control the stack draft within a very small range.

As shown in FIGURE 4, the main shell 16 of the boiler comprises a generally cylindrical sheet of heavy gauge sheet metal. The ends of the boiler space 14 are closed by front and rear heads 40 and 41 respectively which are welded annularly to the main shell 16 as at 42 and 43. The front head 40 is provided with an inspection opening 44 which is closed by -a cap `45 and sealed by an annular resilient seal 46. Thecover plate 4S slidably passes a tiebolt 47 which is welded to the rear headl 41 at 48. The front end 49 of the bolt 47 is threaded to accept a securing nut 50 which is in turn recessed at 51 to accom modate a seal 52. By tightening the nut 50 down. against the seal 52 and the cover plate 45, the cover plate is resiliently tightly sealed against the front head 40 and the boiler chamber 14 is, accordingly, sealed.

In the embodiment of the invention illustrated, the boiler is provided with a hot water heater element 55 which extends generally horizontally within the chamber 14. The coil 55 is provided with an inlet 56 and an outlet 57 which may be connected to the conventional residence hot lwater system. The inlet 56 and outlet 57 are passed through the coverplate and sealed with respect thereto, preferably by means of brazing as at 58. It will be apparent, of course, that the hot water heating element may be dispensed with by providing a coverplate having no apertures for the passage of the coil inlet and outlet 56 andV 57 respectively.

It has been found in actual manufacture of boiler structures in accordance with the present invention that in welding the heads 40- and 41 to the shell 16, at the points indicated `at 42 and 43, a small distortion of the heads occurs causing thel central portion of the heads to bow slightly away from one another. Upon tightening of the nut to secure the coverplate 45 this slight bow in the heads 40 and 41 provides additional resiliency in the system maintaining the coverplate tightly sealed at all times.

In operation, the boiler of the present invention has proved extremely efficient in spite of its compact size. As those skilled in the art of heating are aware, it is desired that the stack temperature for a usual residential heating boiler be less than 600 F. and preferably on the order of 450 to 500 F. It has been found through actual tests, that the boiler above described and illustrated will provide a stack temperature in ythe 450 to 500 range when fired with gas or oil at the rate of 150,000 B.t.u.s per hour with a boiler shell diameter of only fifteen inches and a boiler length of only approximately nineteen inches. Such a boiler shell provides a shell surface area of approximately fourteen square feet which is substantially less than the approximately seventeen square feet ordinarily considered necessary. Further, by constructing the boiler of the present invention with a shell diameter of less than sixteen inches, the boiler comes within the requirements of the miniature boiler code permitting small one inch inspection openings, such as shown at 60 in FIGURE 1. Further, the miniature boiler code permits the use of lightweight sheet metal for the boiler, on the order of 1A thickness. As a result, the expense of the boiler is materially reduced.

As those skilled in the art are aware, the draft ordinarily available in a one story building approximates three inches of water. Since the boiler of the present invention utilizes no fiow restricting baffles, it has been found that substantially all of this draft is available at the combustion chamber 12. In fact, it has been found that this boiler apparatus will provide approximately 2%" of water draft at the fire. In spite of this very favorable draft condition and the absence of flow restricting baflies, the stack temperature remains at the low desired level `due to the extremely efiicient heat transfer afforded by the large crown sheet area, fins 17, and the arcuate channels 20.

As pointed out earlier in the specification, the boiler apparatus of the present invention readily lends itself to slight modification to accommodate varying capacities of fuel burning operation. As illustrated in FIGURE 4, thirteen channels are provided on each side of the boiler. When operating at a capacity of 150,000 B.t.u.s per hour a stack temperature of 460 has been maintained. By eliminating two channels 20 on each side of the boiler shell, without other modification, it has been found that a capacity of 140,000 B.t.u.s per hour will provide the eminently satisfactory stack temperature of approximately 480 F. At the rating of approximately 140,000 B.t.u.s per hour for one gallon of oil, it has been found that employing .85 gallons per hour, or approximately 120,000 B.t.u.s per hour, a stack temperature of approximately 480 F. is achieved by utilizing only seven channels 20 on each side of the boiler shell. Likewise, at .75 gallons per hour, or approximately 105,000 B.t.u.s per hour, that stack temperature is maintained by utilizing five channels 20 on each side of the boiler shell. At the rate of approximately .5 gallon per hour the stack temperature of approximately 480 F. is maintained by utilizing only three channels 20 on each side of the shell. Thus, by modifying the number of channels 20, without making other modifications of any nature, such as for example by adding baflies or the like, the capacity of the boiler is simply modified and the stack temperature is maintained at its efiicient, desired, level.

As will be seen from a consideration of the specification and drawings as hereinabove described, the construction of the present invention provides an extremely cornpact and eliicient boiler unit for heating purposes. It will be apparent to those skilled in the art that variations and modifications may be made in this structure without departing from the scope of the novel concepts thereof and it is, accordingly, intended that the scope of the present invention be limited solely by that of the hereinafter appended claims. For example, in the form of the invention illustrated, the firebox and combustion chamber are arranged generally for use with conventional oil burners. Where it is desired that gas be employed as a fuel, it is ordinarily unnecessary to provide a fire brick lined en- 6 closure and the combustion chamber may be lowered to provide still greater compactness.

A further modification that may be made within the purview of the present invention lies in the positioning of the fins 17. In the embodiment of the invention illustrated in the drawings and described specifically above, the fins 17 are parallel to the longitudinal axis of the boiler shell 16. It is preferred that the fins be positioned in this manner since to do so permits utilization of a substantially perfectly straight fin welded to the shell along a generally straight line. However, the fins 17 may eX- tend longitudinally of the shell 16 in the form of a helix on the surface of the shell 16. Similarly, the fins 17 could lie generally transversely of the shell 16. In both these latter cases, however, the fins must be constructed in a curved form and the lines of attachment are substantially complicated.

I claim as my invention:

1. A boiler comprising means defining -a combustion chamber, means introducing fuel into said combustion chamber for comb-ustion thereof, heat transfer apparatus for transferring the heat of combustion of said fuel to a heat transfer fluid, comprising a generally cylindrical horizontally disposed boiler shell of generally circular crosssection positioned .above said combustion chamber, an outlet positioned above said shell for directing the products of combustion passing upwardly around said shell to an outlet stack, means defining passageways upwardly around both sides of said shell to said outlet, each said passageway including a plurality of arcuate generally U- shaped channels having the legs thereof secured in heat conducting relation to said shell and having the bottom of the channel open to the combustion chamber and the top open to the outlet, the bight of the U providing a peripheral surface facing inwardly toward the periphery of said shefll for forcing the upwardly flowing products of combustion to flow in close contact with the upper surface of said shell or with the channel to thereby conduct heat from the products of combustion to said fluid in an efficient manner.

2. A boiler comprising means defining a combustion chamber, means introducing fuel into said combustion chamber for combustion thereof, heat transfer apparatus for transferring the heat of combustion of said fuel to a heat transfer iuid, comprising a generally cylindrical horizontally disposed boiler shell of generally circular crosssection positioned above said combustion chamber, an outlet positioned above said shell for directing the products of combustion passing upwardly around said shell to an outlet stack, said shell having a plurality of longitudinally extending fins projecting downwardly from the surface thereof and facing the combustion chamber, means defining passageways upwardly around both sides of said shell to said outlet, each said passageway including a plurality of arcuate generally U-shaped channels having the legs thereof secured in heat conducting relation to said shell and having the bottom of the channel open to the combustion chamber and the top open to the outlet, the bight of the `U providing a peripheral surface facing inwardly toward the periphery of said shell for forcing the upwardly flowing products of combustion to flow in close contact with the upper surface of said shell or with the channel to thereby conduct heat from the products of combustion to said fiuid in an eflicient manner.

3. The boiler constructed in accordance with claim 1 wherein means is provided for adjusting the cross-sectional area of said outlet for restricting the rate of flow of products of combustion therethrough.

4. The boiler constructed in accordance with claim 1 including a pair of heads enclosing the opposite ends of said cylindrical shell, a tie bolt rigidly secured to one of said ends and passing through the other said ends, said Y 8 other of said ends having an enlarged opening concentri- References Cited in the le of this patent calliy lof said tie bolt a cover slidably mounted relative to UNITED STATES PATENTS said tie bolt for seahngly engaging the other head on the outside thereof, and securing means for co-operation with 797,960 Junkers Aug 22' 1905 said tie -bolt and said cover to simultaneously secured said 5 216171392 Donohue NOV' 11' 1952 cover to said heads and reinforce said heads against inter- FOREIGN PATENTS Dal pressures m Said Shen- 712,756 Great Bn'tain July 28, 1954. 

